The effect of age and dietary protein sounce on free amino acids, ammonia, and urea in the blood plasma of the calf

1966 ◽  
Vol 17 (2) ◽  
pp. 237 ◽  
Author(s):  
J Leibholz

The concentrations of most of the free amino acids in the blood plasma of the calf decreased with increasing age between 3 days and 24 weeks. This effect was significant for serine, proline, methionine, leucine, glutamine, lysine, and histidine while the concentrations of aspartic acid, glutamic acid, valine, cystine, and ornithine remained constant. Dried skim milk as a protein supplement in the calf's diet resulted in a higher concentration of free amino acids in the blood plasma than did meat meal. The relative proportions of the free amino acids in the plasma were related to their concentrations in the diet. Addition of methionine to calf diets increased the free methionine concentration in the blood plasma.

1986 ◽  
Vol 55 (3) ◽  
pp. 651-658 ◽  
Author(s):  
Ronald O. Ball ◽  
Henry S. Bayley

1. Piglets were weaned at 3 d of age and reared to 2.5 kg on a liquid diet in which the protein was supplied by dried skim milk and a mixture of free amino acids. The oxidation of L-[l-14C]phenyIalanine was measured as an indication of the partition of amino acids between retention and catabolism in pigs (2.5 kg) offered meals containing vaned concentrations of crude protein (nitrogen x 6.25).2. The dietary protein concentration was varied either by increasing the inclusion of a mixture of free amino acids in a series of diets containing 100 g protein/kg from skim milk, or by increasing the level of inclusion of the skim milk in a series of diets containing the equivalent of 100 g protein/kg from the free amino acid mixture.3. The oxidation of phenylalanine was minimized by dietary protein concentrations of 240 and 258 g/kg for the diets containing increasing concentrations of free amino acids or skim milk respectively.4. These results show that a mixture of free amino acids is used more effectively than intact protein for promoting retention of essential amino acids.5. The recovery of radioactivity in expired carbon dioxide was inversely related to the recovery of radioactivity in liver tissue when the concentration of dietary crude protein was increased from deficient to adequate, demonstrating that the fractional oxidation of the indicator amino acid was inversely related to protein synthesis.


1988 ◽  
Vol 255 (2) ◽  
pp. G143-G150 ◽  
Author(s):  
R. P. Ferraris ◽  
J. Diamond ◽  
W. W. Kwan

Uptake of the dipeptide L-carnosine was measured in everted intestinal sleeves of mice whose dietary protein level or else proportion of protein in the form of free amino acids was varied experimentally. Carnosine uptake was highest in the jejunum, regardless of ration. Compared with a low-protein (18%) ration, a high-protein (72%) ration stimulated carnosine uptake by 30-70% in duodenum and jejunum (but not in ileum). This stimulation was observed even in the presence of peptidase inhibitors that inhibit cell surface hydrolysis of dipeptides. Measured carnosine hydrolysis was low or negligible. Carnosine uptake was the same in mice fed 54% unhydrolyzed casein, 54% partly hydrolyzed casein, and 54% free amino acids formulated so as to stimulate a complete hydrolysate of casein. Thus carnosine uptake is regulated by dietary levels of amino acids, peptides, and proteins, all of which seem equally effective at inducing carnosine transporters.


Author(s):  
Chuang Chih-Kuang ◽  
Lin Shuan-Pei ◽  
Lee Shyue-Jye ◽  
Wang Tuan-Jen

2020 ◽  
pp. 152-158
Author(s):  
L. N. Keda ◽  
A. V. Naumov ◽  
V. YU. Smirnov

Objective: to determine the possibilities for prediction and diagnosis of congenital fetal malformations and chromosomal abnormalities on the basis of the study of the levels of amino acids and their nitrogen-containing derivatives in blood plasma of pregnant women with pathological conditions requiring artificial termination of pregnancy. Material and methods. The content of free amino acids and their nitrogen-containing derivatives was studied in 104 pregnant women having congenital malformations and chromosomal abnormalities in their fetuses at 13-22 weeks` gestation (group I) and 25 women with physiological pregnancy (group II). The amino acid level was determined by the high-performance liquid chromatography method. Results. The levels of 14 out of the 26 studied amino acids in the blood plasma of the pregnant women of group I were statistically higher than those of the women in group II. ROC analysis was used to determine six amino acids (glycine, α-aminobutyric acid, hydroxylysine, glutamic acid, citrulline, serine) and their threshold values which with high accuracy (85.3 %) allow of predicting congenital fetal malformations and chromosomal abnormalities. A prognostic model making it possible to determine high probability of congenital fetal anomalies based on the determination of the concentration of 5-hydroxytryptophan, glycine, asparagine, and serine in blood plasma of pregnant women has been developed. Conclusion. The study of the levels of amino acids and their nitrogen-containing derivatives in plasma of pregnant women at 13-22 weeks` gestation can be used for prenatal diagnosis of congenital fetal malformations and chromosomal abnormalities, as well as used as an additional criterion for making the decision on the necessity for artificial termination of pregnancy upon fetal medical indications.


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